Keen Warren withdrew her plea of not guilty and changed her plea to guilty during Tuesday's court appearance. During the hearing, prosecutors outlined evidence they would have brought forward during the trial that they say implicated Keen Warren in the fatal shooting on May 26, 1990 -- including testimony from witnesses from a local costume shop that placed her buying a clown costume and wig approximately two days before the incident. Warren's son, Joseph Ahrens, was at home at the time of the shooting, authorities said